| 摘要 |
A tool having a first lower sub end, a second upper sub end, and an extensible joint connecting the first and second sub ends. The joint has a first inner latch piece connected to the lower sub end, and a second outer latch piece connected to the upper sub end, and a stationary restraining collar. The joint, in a latched position, has the outer latch piece latched to the inner latch piece and the inner and outer latch pieces restrained from unlatching by the restraining collar. The joint, under tensile force, unlatches into an unlatched position by the inner latch piece pulling the outer latch piece through the restraining collar into a position where the inner and outer latch pieces are free to separate. An impact force is generated from the tensile force when the joint unlatches and reaches a maximum extension. |
